


Monstrous Ambitions

by KRSCZ



Series: What makes them "Monsters" [2]
Category: Undertale (Video Game)
Genre: Gen
Language: English
Status: In-Progress
Published: 2016-08-08
Updated: 2016-08-16
Packaged: 2018-08-07 09:50:22
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 3
Words: 4,013
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7710472
Author URL: https://archiveofourown.org/users/KRSCZ/pseuds/KRSCZ
Summary: <blockquote class="userstuff">
              <p>There are some people in the world who will go as far as making people suffer just to satisfy their own personal needs.</p><p>The Doctor is one of them.</p>
            </blockquote>





	1. Experimentation

**Author's Note:**

> And finally, it's here! Another piece of the puzzle piece that is this story. 
> 
> For more context, visit my Tumblr. I made a post about how this series will work over there. 
> 
> http://krscz.tumblr.com/

**Summary for the Chapter:**

> If scientists agree on one thing, it's that everything must be tested.

Papyrus woke up bright and early today. He was so excited to train; he wanted nothing more than to capture a human so he could become popular. As he went downstairs, he saw his brother Sans getting ready to leave.

 

“morning, paps. your training starts today, right?” Sans said as he put on his lab coat. Sans worked as a lab assistant for the Royal Scientist, Dr. W.D. Gaster. Papyrus had never really met Gaster himself, but he never heard any complaints about him from Sans, so he never really paid any mind to it.

 

“YES, MY TRAINING WILL START TODAY. I WILL CAPTURE A HUMAN! I WILL BE THE ONE!” Always excited to try and capture a human.

 

“heh. well, good luck bro. alright, time for work. g said something important is happening today. pretty curious as to what that is, so i’m leaving early.” Gaster was a very interesting man, from what Sans had said about him. And whenever Gaster would call Sans, they would speak in a different language. Papyrus didn’t really know anything about this language, though. Papyrus sat for a moment and thought to himself of what Gaster had planned. However, his train of thought was stopped at the sound of Sans’s phone ringing. He checked to see who it was, and then immediately picked up.

 

“ **heya, g. whats up? I was just about to head out to the lab.** ” Sans spoke in that weird language again, obviously to Gaster.

 

“ **Sans, today is going to be a very important day. Please hurry.** ” Papyrus was able to hear the voice of a man speaking the same language to Sans.

 

“ **huh. alright. ill see you in a bit, then.** ” Sans hung up the phone. “welp, duty calls. see ya tonight, paps.” With that, Sans left the house and made his way to Gaster’s lab. Papyrus continued to ponder as to what Gaster had planned for Sans today, but he soon realized that it was for the best that he forgets about it and moves on. After all, he had training today. This would be his first day training with Undyne, and he wanted to make sure that he was mentally prepared for what might happen. He had to be the one to capture a human. He just had to. He wanted to make everyone proud. He put on his red scarf and walked out of the house, eager to get to Undyne’s house. Undyne lived in Waterfall, so Papyrus decided to go to the River person and take a ride there.

 

“ONE RIDE TO WATERFALL, PLEASE?” Papyrus always thought the river person was interesting. In truth, nobody really knew what was under that hood. Nobody even knew if it was a guy or a girl. Papyrus stepped onto the boat, and without any word, they started on their way to Waterfall. “THIS MAY SOUND ODD, BUT… COULD I PERHAPS GET YOUR NAME?”

 

“Tra la la. What’s my name? ... It doesn’t really matter…” The river person spoke calmly, and ominously as always. Within a few moments, they would be in Waterfall. Papyrus was excited to see Undyne and to train with her. He was prepared to become a warrior.

 

 

_Meanwhile…_

Sans made it to the lab. He looked around at all the basic lab equipment there. He softly chuckled to himself, and walked into the “bathroom”. As he walked in, he started to descend down to the True Lab where Gaster had all of his actual equipment. As he walked out of the elevator, he turned to his left to see Gaster waiting for him.

 

“Ah, there you are, Sans. Come with me, we have a big experiment to do.”

 

“alright. hey, i’ve been meaning to ask… has asgore gotten back to you?”

 

“Yes, he has and he’s accepted. Today, we will be working with the human soul he gave us.” It made a bit more sense to Sans now. Gaster had always wanted to experiment with human souls. Asgore had only two in his possession at this point, including the one Gaster was going to be experimenting with.  Gaster was always going on about how a human soul could potentially hold secrets to the universe, but Sans always just brushed it off as Gaster getting ahead of himself. The two of them walked towards one of the experimentation rooms. “Okay, Sans. While you were on your way, I started research on this soul. And what I found may be the key to our goal, to replicate a human soul. Take a look at this.” Gaster brought something up on the computer and showed it to Sans. It showed the human soul and there seemed to be… some kind of energy flowing through it.

 

“is that… energy flowing through it? what is that, g?” Sans had some interest in human souls. Not as much as Gaster did, but still.

 

“This is what differentiates us from humans. This is a form of energy that I can’t seem to find in any monsters I’ve ever dealt with it. This energy form seems to be… Determination.” Sans had heard of Determination before, but never as a source of energy. Gaster put his fingers to the keyboard and started typing away, causing machines to move around and do various different things. While he was doing this, Sans couldn’t help but shake the feeling that Gaster’s curiosity with human souls would go too far. Gaster was a very curious man, being a scientist and all; but a human soul is something he had never gotten to experiment with. He just had to make sure Gaster didn’t get too crazy with his research. He had to, for not only his sake, but for Gaster’s sake.

 

“so, uh. what’re you gonna do with this ‘determination’ stuff?” Gaster stopped pressing buttons and walked over to the vial that a certain substance was being poured into, assumedly Determination. He took the vial and slowly filled a needle with it.

 

“I’m going to do something that may be risky… but I absolutely have to do this. I’m going to inject myself with the Determination.” Sans’s eyes seemed to widen. This was exactly what he didn’t want to happen. If Gaster were to have Determination inside of him, who knows what he would do? He sighed, and realized he had only one choice.

 

“hey, g… inject me instead. you need to be as normal as you can so you can scan me to see if it does anything to me, and you’re much better at that than i am.” Gaster looked at Sans in the eyes, then softly sighed.

 

“Alright, I’ll inject you with it then. We don’t know how this will turn out. Are you sure you want this?”

 

“positive.”

 

“Alright… here goes something.” Gaster slowly began to inject Sans with the Determination. As all of the Determination was injected into Sans, he started to twitch in place. Sans began to cough and his legs felt weak.

 

“w-whoa… t-that’s some… strong stuff…” Sans continues coughing, it sounded like he was in pain. He looked as Gaster. When Gaster looked back at him, he saw that one of his eyes was now glowing a light blue color, something that Gaster had never seen before. This must be an effect of the Determination.

 

“Sans! How do you feel?” Gaster had a weird mixture of curiosity and concern in his voice.

 

“i-i’ll be okay… hey, can we… take a break or something? i… don’t feel so hot…” Gaster sighed and pat Sans on the shoulder.

 

“Go home, Sans. Come back tomorrow. You’re in no condition to be working right now. I’ll handle the Determination for now.” Sans slowly nodded and made his way out of the True Lab. He really didn’t feel good, he needed to get home and lay down for a while.

 

_Meanwhile…_

 

 Papyrus had to leave Undyne’s house early. The training was going well, but Undyne had Royal Guard duties to attend to. Papyrus decided to just go home instead of waiting around for her to be done. He rode the river back to Snowdin and walked into his home. As he walked in, he immediately noticed Sans laying on the couch, coughing up a storm.

 

“SANS! ARE YOU OKAY??” Sans seemed lifeless, to the point where Papyrus would have thought he was asleep or even dead if he wasn’t coughing so much. No matter what he did, Sans would stay absolutely still. He was so scared that something had happened to him while he was at work. He decided he would call Undyne about it.

 

When Sans wasn’t around, Papyrus felt so alone. He needed someone there with him. 


	2. Revelation

**Summary for the Chapter:**

> Papyrus is worried sick.

**Notes for the Chapter:**

> You might think things are gonna get... REALLY weird at one point... but they won't lead to what most people will think it'll lead to!
> 
> You'll see what I mean.

Papyrus didn’t know what to do. Sans was completely unresponsive, and he didn’t know why. Having no idea what to do, he decided to call Undyne. It had been a few hours now since Papyrus left Undyne’s house, he could only hope that Undyne was available.

 

“Papyrus? What’s up?”

 

“UNDYNE… IT’S MY BROTHER, SANS. THERE’S SOMETHING WRONG WITH HIM…”

 

“Something wrong with him? What do you mean, Papyrus?”

 

“HE’S NOT TALKING. HE’S NOT EVEN MOVING! THERE’S SOMETHING SERIOUSLY WRONG…”

 

“Calm down, Papyrus. What happened last time you saw him? What was he talking about?”

 

“HE SAID HE WAS GOING TO WORK, TO THE LAB. WHEN HE LEFT, I LEFT FOR YOUR HOUSE. WHEN I GOT BACK, I SAW HIM JUST… ON THE COUCH, NOT MOVING OR RESPONDING TO ANYTHING I SAY. HE’S NOT SLEEPING… HE’S JUST… LIFELESS…” Papyrus sounded like he was about to break out into tears as he spoke. Undyne had never heard someone so… sad before.

 

“Papyrus, listen. Your brother will be fine, but you need to give him time. Why don’t we go to the Lab in the mean time? If we want to find out what’s wrong with him, then we should find success there.

 

“RIGHT… BUT I CAN’T LEAVE MY BROTHER ALONE UNDYNE. I REALLY CAN’T.”

 

“Alright, that’s fine. I’ll go to the Lab right now. You make sure Sans stays safe, and call me right away if he wakes up. I’ll talk to you soon.”

 

“GOOD LUCK, UNDYNE…” Papyrus hung up and went back to Sans. Sans was still unresponsive after all these hours. Papyrus could only hope that Undyne would be able to do something, to at least find out what caused this.

 

_Meanwhile…_

 

Undyne left her house and made her way to Hotland. She left her armor behind, because she knew that it would slow her down, especially in Hotland. The walk to Hotland was not a long one, but it felt really long for her. Even though Undyne had just recently met Papyrus, she felt bad for him. He sounded so… sad. He could tell that Papyrus really cared about his brother. He was a lab assistant, one to the Royal Scientist at that. Within a few moments, she found herself in Hotland.

 

“Ugh… man, I really hope there’s a bathroom in that lab…” As she said that, she decided to reach into her pockets and call Papyrus. However, when she reached for her phone, she realized that she had left it at her house. “Ugh… god damnit…” Undyne knew she needed her phone, but the lab was so close and she desperately needed to pee. Undyne ran to the Lab from there, being unable to hold it in for much longer. She got into the lab and ran towards the bathroom.

 

_Meanwhile…_

Papyrus had calmed down a little. He was starting to accept that Sans wasn’t going to be waking up anytime soon. Though, when he looked over to Sans, he noticed something… odd. There was a light blue glow coming from the couch Sans was on. He noticed then that he never looked at Sans when he found him. He slowly walked over to Sans and turned him over, and saw a bright blue light emanating from his eye socket. Papyrus gasped and fumbled for his phone, and quickly called Undyne. One ring… two rings…

 

**But nobody came.**

_Meanwhile…_

Undyne flushed the toilet and got up from her seat. Now that she was relieved, she wanted to go back home and get her phone before doing anything. However, something stuck out to her in the bathroom. There seemed to be some kind of a floor panel that she didn’t seem to step on. She took a deep breathe, and stepped on it. As she stepped on it, the bathroom slowly started to descend. She instantly began to panic. What was she to do? The bathroom was… an elevator? An elevator that led to where? Her thoughts scared her to the core, she had no idea what to expect. A few moments later, the elevator stopped descending, and she heard noises, like someone was talking in some… alien language. She had never heard it before, but it made her more nervous. She walked out of the elevator and began walking.

 

“ **Yes YES! This is outstanding!** ” This voice was definitely familiar to her, but from where has she heard it? It was hard to tell with the alien language. However as she walked closer, she saw a dark figure. She gulped and spoke softly to it. She’d never been so scared in her life.

 

“Um… excuse me?” The dark figure jumped. He recognized this voice, but never expected to hear it in here of all places.

 

“…Undyne? Is that you?” The dark figure turned around and revealed himself as the Royal Scientist himself, Dr. W.D. Gaster. The sight of a familiar face instantly calmed Undyne’s nerves.

 

“Gaster? What… what is this place?!” Gaster was still shocked to see someone besides Sans in this secluded place.

 

“I’m sorry Undyne, I didn’t mean for anyone to come here. Is there a reason you’re here? I don’t want to keep anyone here for too long if I can help it.” Gaster spoke calmly, trying not to startle her. He wanted to make sure nobody else found this place.

 

“I came to the Lab looking for you. Something is wrong with Sans. His brother has been worried sick about him because Sans has been completely unresponsive. Do you know what happened to him?” Gaster looked down, then turned away. As guilty as he felt… a sinister smile still managed to grow on his face.

 

“Oh, Sans? Me and Sans were experimenting with something. However, he felt sick. I sent him home and told him to get rest. The effects of what happened should fade after a few hours of sleep. Oh, well since you’re here… can you help me with something? I promise it take long.”

 

“I would love to help you Gaster, but I have to get back to Papyrus. He’s worried sick-“ Undyne’s words were stopped by a tentacle grabbing her and throwing her down onto an examination table. “Gaster..?!” The tentacle held her down, and seemed to be coming from Gaster. Another one came out from under his robe, and covered her mouth.

 

“You see Undyne… me and Sans were experimenting with a substance we found in humans, a form of energy. We called this… Determination. Sans wanted to be injected with some of it. However… it had a bad side effect on him. But, I was too curious. I decided to give myself some… and now look at me! More powerful than ever… but unfortunately I can’t run these experiments and tests on myself.” The sinister smile grew bigger on his face, as he grabbed a needle from the table. “That’s where you will be coming in, Undyne.” Undyne struggled and tried her hardest to get away from the tentacles, but she just couldn’t muster up the strength. Gaster took the needle and injected Undyne with the Determination. Her struggles became more apparent and her muffled screams got louder, but eventually her eyes closed and she drifted to sleep. Gaster laughed to himself and dismissed the tentacles that had her restrained. As much as he would love to run numerous tests on Undyne, there was something stopping him. He needed more. He couldn’t settle for only one subject, he needed more. He needed to take Sans and bring him back so he could run tests.

 

And while he was there, he could take his brother too.  

**Notes for the Chapter:**

> I bet people expected tentacle rape. None of that!
> 
> Not without warning, at least.


	3. Deceit

**Summary for the Chapter:**

> Gaster is a tricky one,

**Notes for the Chapter:**

> SO SORRY that this is so late. I've been really busy recently. Hopefully I never take this long again...

Gaster decided it was time to bring Sans back to the lab. He would have to make up a lie to bring Papyrus along, too. He had never met his brother, nor has he heard much about him. Sans didn’t like to bring him up much, for whatever reason. Gaster was curious to see what kind of personality Papyrus had. But before anything, he wanted to relocate Undyne.  He channeled his energy and teleported away from the True Lab to the final room of The Core. He placed her down to the side of the room and left the room. Once outside, he pressed a button and locked the doors. Undyne will have no way of getting out. Gaster hadn’t fully finished creating The Core yet, so nobody was allowed to enter. Once the doors were fully locked, he teleported out of The Core and to Snowdin. He didn’t want to make much of a scene if he didn’t have to. He knocked on the door to Sans’s house, and out came a tall skeleton, who looked almost nothing like Sans.

 

“HELLO THERE. WHO MIGHT YOU BE?” This skeleton was very loud, a complete opposite to Sans. Maybe that’s why Sans never brought him up.

 

“Hello there. I was wondering, might you be Sans’s brother, Papyrus?” Papyrus looked surprised that someone knew Sans but didn’t know him. Sans was never really the popular type.

 

“UM, YES… WHO MIGHT YOU BE, THOUGH?” Gaster gave Papyrus a warm smile, not trying to show any of his true intentions to him.

 

“It’s nice to finally meet you, Papyrus. My name is W.D. Gaster. I am the Royal Scientist for King Asgore, and I work with Sans on a daily basis.” Gaster held out his hand, prompting Papyrus for a hand shake. Papyrus didn’t know much about Gaster, aside from the fact that he worked with Sans, and that he spoke that weird language. 

 

“OH! IT’S A PLEASURE TO FINALLY MEET YOU, DOCTOR GASTER.” Papyrus held his hand out and shook Gaster’s hand.

 

  
“Please, just call me Gaster. No need to be so formal. I was wondering, how is Sans? I sent him home early due to him not feeling so well, is he feeling any better now?” Papyrus shivered and looked behind him, at his brother.

 

“HE’S… NOT DOING SO WELL. THERE’S SOMETHING WRONG WITH HIM, AND I DON’T KNOW WHAT IT IS.”

 

“May I come in and take a look at him? I think I can help with this.”

 

“YES, PLEASE DO. I FEAR THAT HE MAY NEED IT BADLY.” Papyrus walked out of the way and let Gaster in to the house. Papyrus closed the door behind him and turned to Sans, who Gaster was already standing by. Gaster kneeled down and looked into Sans’s eye sockets. His eye was still glowing a light blue color, which made Gaster flinch a bit. Gaster had seen it before, but it was significantly brighter now.

 

“Hmmm… Papyrus, I feel as if I need to take him to the Lab with me. I don’t have the proper equipment here. Would you like to join me?” Gaster still gave the same warm smile that he did before. If there was one thing Gaster knew, it was how to deceive people.

 

“YES, PLEASE TAKE ME WITH YOU. I DON’T WANT TO LEAVE SANS ALONE.”

 

_Meanwhile…_

Undyne’s vision was blurry, but she was awake. In a place she had never seen before, at that. What happened to her? She couldn’t remember. She remembered talking to Papyrus… and she remembered not having her phone on her. As for where she was, it was anyone’s guess. She had never seen such a place, and she had never been surrounded by such a… deafening silence. She remembered weird noises… and needles. She got up and looked around, but there seemed to be no exit. She walked over to what looked like a door, but it wouldn’t budge. She started banging on the door as hard as she could.

 

“HEY! LET ME OUT OF HERE, DAMN IT!” Undyne yelled as hard as she could, but there was no answer. She was really trapped in that place… but she refused to stay there. She felt one of her eyes burning, like a fiery rage was building up inside of her. She didn’t know what was happening to her, but as much as it hurt, she felt so… angry. She knew something happened but she didn’t know what it was, and she didn’t know why she was being held captive here. She was so angry… and she couldn’t take it anymore. Suddenly, Undyne’s mind went numb. Her body seemed to move with a will of its own, and she couldn’t even comprehend what was happening. Her muscles moved on their own, as a blue spear was summoned to her hands, and she smashed it into the door, cracking it open, as she proceeded to kick down whatever was left of it. She panted. She had exerted so much energy, and she didn’t even know how she did it. She didn’t even know what happened. She looked at the spear in her hands… where did it come from? Did she… create that with her own rage? She was so confused… but that didn’t matter as much as something else. She still had to find out where the hell she was and how the hell she was going to get out. It looked… like a giant machine. As if someone created this on their own. But… who could do that? She was clueless on that for the time being. Regardless, she decided to start exploring. While she was there, maybe she could find clues as to what happened.

 

_Meanwhile…_

 

“In here, Papyrus. There’s a secret passage in the bathroom.” Papyrus seemed extremely confused at that. Then again, who wouldn’t be? There aren’t many people who have secret passages in the bathroom. Regardless, Papyrus followed Gaster, who had Sans over his shoulder, into the bathroom. Once they got on, they began to descend into the True Lab. Papyrus stepped out slowly as they got there, somewhat scared of where he was.

 

“WHERE… WHAT IS THIS PLACE?” Papyrus spoke with fear in his voice.

 

“This Is my lab. The True Lab, if you want to call it that. Come with me, I need to take Sans to the examination room.” Gaster led Papyrus to the examination room, and put him down. “Papyrus, I’ve been meaning to ask… do you have any goals in life?”

 

“GOALS? WELL, YES… I WANT TO BE THE ONE TO CAPTURE A HUMAN.”

 

“Ah, you want to be in the Royal Guard, then? How has that been going for you?”

 

“WELL… I DON’T THINK I’M STRONG ENOUGH FOR IT. I’VE BEEN TRAINING WITH UNDYNE, BUT I WON’T THINK I’M STRONG ENOUGH FOR IT YET.” Gaster chuckled, everything was falling into place for him.”

 

“Papyrus, I think I can help with that. You see, me and Sans were experimenting with something today… something called Determination. I assume you haven’t heard of it, have you?”

 

“DETERMINATION? NO, I CAN’T SAY I HAVE… WHAT IS IT?”

 

“Determination is what separates Humans from us. Determination is why Humans won the war against us many years ago… it’s what makes them powerful. I’ve been studying Determination, and I found that when someone is injected with Determination, their power increases exponentially! Papyrus, if you want, I can inject you with Determination, and you’ll be stronger than you could ever imagine!” Papyrus looked so excited. He could finally be stronger. He could finally show his worth to Undyne, and prove that he was strong. And when Sans woke up, he would be so proud of how strong he was.

 

“OKAY, INJECT ME WITH THE DETERMINATION. I WANT TO BE STRONG!”

**Notes for the Chapter:**

> The action is gonna be picking up really soon...


End file.
